var fs = require('fs')

let arr = fs.readFileSync('./SDdata.json')
arr = JSON.parse(arr)
arr2 = unique(arr)
console.log(arr2.length)



function unique(arr) {
    var hash = [];
    for (var i = 0; i < arr.length; i++) {
        for (var j = i + 1; j < arr.length; j++) {
            if (arr[i].ID === arr[j].ID) {
                ++i;
            }
        }
        hash.push(arr[i]);
    }
    return hash;
}